Wild yeasts are brewing up batches of trendy beers

Using scavenged microbes for fermentation brings out the funky and sour flavors

MICROBE BREWS Scientists are looking for a few good yeasts to enhance beer brewing. Each flask (above) contains the same liquid ingredients and a different kind of yeast.

M. BOCHMAN

Craft brewers are going wild. Some of the trendiest beers on the market are intentionally brewed to be sour and funky. One of the hottest new ingredients in the beverages: Yeast scavenged from nature.

Unlike today’s usual brewing, which typically relies on carefully cultivated ale or lager yeast and rejects outsider microbes, some brewers are returning to beer’s roots. Those beginnings go back thousands of years and for most of that time, the microbes fermenting grain into alcohol were probably wild yeast and bacteria that fell into the brew. Now local microbes — in some cases with the help of scientists — are being welcomed back into breweries.

Wild and sour beers are a niche, but growing segment of the craft brewing market, says Bart Watson, chief economist of the Brewers Association. Last year, more than 245,000 cases of wild and sour beers were sold and sales are up 9 percent so far this year.

For geneticist Maitreya Dunham, wild, funky and sour beers aren’t just a market trend; they are ecological microcosms. Dunham’s lab group at the University of Washington in Seattle uses yeast to study genetic variation and evolution. She got interested in beer when her husband took up home brewing.

FUNGI FERMENTATION A strain of Pichia kudriavzevii yeast forms a biofilm at the interface of liquid and air in a lab flask. Researcher Matthew Bochman is testing many strains and species of wild yeast for their beer-brewing properties.

M. BOCHMAN

In the bottom of his five-gallon fermentation bucket, the yeast formed a thick mat that bubbled rapidly. “That’s not how we grow yeast in the lab,” Dunham said. She wanted to test a new technique her lab had developed to identify wild yeast in their natural habitat. And what better habitat to explore than a barrel of beer?Dunham teamed up with a brewer who made a wild beer with microbes from a warehouse. “Whatever is living in the old warehouse ended up in the beer,” she says. On a lab outing to the brewery, Dunham and her team took samples from beer barrels, marveling at the thriving mass of microbes gurgling inside. “You could see it being alive in there.”

DNA tests revealed that four kinds of bacteria and four kinds of yeast, including a newly identified hybrid yeast, lived in the wild brew, Dunham and colleagues reported June 15 on bioRxiv.org. The hybrid doesn’t have a name yet, because Dunham is still trying to identify its parents. One is Pichia membranifaciens, but the other is an unknown fungus P. membranifaciens is a food spoiler, and no lightweight: It can handle up to 11 percent alcohol.The other parent’s identity and attributes aren’t known, and that ID can take time. People have known for a long time that lager yeast Saccharomyces pastorianus is a hybrid, but scientists didn’t identify both of its parents until 2011.

As excited as Dunham is to find a hybrid yeast, she’s not sure that it will take beer brewing by storm. Her lab brewed a small batch of “science beer” with the hybrid yeast. The yeast didn’t make much ethanol or other flavor compounds. “It didn’t do much on its own,” she laments. But she hasn’t given up hope. Sometimes a yeast needs bacteria or other fungi to really shine. Maybe, she says, “when it’s mixed in with all its friends, it may bring something interesting to the party.”

A Facebook group of home brewers called Milk the Funk is about to help her find out. People from the group saw Dunham’s study on bioRxiv.org and volunteered to ferment beers with and without the hybrid. “I’m about to have a couple dozen people doing experiments for me,” Dunham says. “In fact, they’re going to send me free beer, although it may be weird beer.” (“Funk is one of the flavors they go for in these weirdo beers,” Dunham explains. Descriptions of funk encompass barnyard tastes and smells such as goat, horse blanket, urine, sweat, cheese and manure, as well as spicy notes and complex flavors of clove, smoke, Band-Aid, bacon and bitter, says fellow scientist and yeast hunter Matthew Bochman. “Funk basically covers anything ‘weird’ in beer that might be interesting or pleasant in small amounts but off-putting at higher concentrations.”)

LOCAL SOURCING Old Warehouse beer was brewed from microbes found in an old warehouse, including a new hybrid yeast.

IVAN LIACHKO

Bochman, a biochemist at Indiana University Bloomington and a self-professed yeast whisperer, is also bagging new kinds of wild yeast. Bochman, who studies how cells keep their DNA intact, was a home brewer for years before moving to Indiana. He soon made friends with many local craft brewers there. In 2014, he met brewer Robert Caputo, who wanted to make an all-Indiana beer. There were farmers in the state growing hops and malt grains. Indiana water was plentiful. “The missing ingredient was the Indiana yeast,” Bochman says. Caputo asked Bochman to help him find the missing microbe. “So we went yeast hunting.”

That spring and summer, Bochman collected about 100 strains of yeast. “Whenever I was out and about I would grab something — a piece of a bark, a berry — bring it back to the lab and get yeast from it.” The microbes are everywhere, he says. “It’s hard not to find yeast.”

But not just any yeast will do. For beer brewing, he needed to find yeast that eat the sugar maltose in the wort — the liquid extracted from grain mash that will be fermented into beer. Yeasts used for brewing also have to be tolerant of hops, which make weak acids that might slow yeast growth. The yeast must be able to live in 4 to 5 percent alcohol. In addition, the microbes have “to smell and taste at least neutral, if not good,” Bochman said.

But in 2015, a batch of wild beer brewed in an open vat in a vacant lot in Indianapolis by Bochman’s friends at Black Acre Brewing Co., yielded a winner. Among the four species and six strains of yeast in the beer was a Saccharomyces cerevisiae strain called YH166. S. cerevisiae is the species of yeast used to brew ales and wine and to make bread. YH166 lends beer an aroma that is “an amazing pineapple, guava something. Like an umbrella drink,” says Bochman.

He doesn’t yet know what chemicals the yeast makes to produce the tropical fruit scent. He puts his money on one of the sweet-smelling esters yeast use to attract the fruit flies that can give the fungi a lift — sort of a microbial version of a ride-hailing app.

HYBRID POWER A new hybrid yeast was found in a barrel of wild beer. Home brewers are testing the characteristics that the yeast, shown above growing in a lab dish, brings to beers.

IVAN LIACHKO

Sour beer brewers may also benefit from Bochman’s bio-prospecting. Sour beers generally contain lactic acid bacteria in addition to yeast. Brewers need separate equipment for brewing sour beers, because it’s difficult to get rid of all the bacteria in order to brew a nonsour beer.Among 54 species of yeasts Bochman and colleagues investigated, he found five strains that can make both alcohol and lactic acid to brew sour beers without troublesome bacteria. The researchers described the five sourpusses — Hanseniaspora vineae, Lachancea fermentati, Lachancea thermotolerans, Schizosaccharomyces japonicus and Wickerhamomyces anomalus — July 28 on bioRxiv.org. Bochman and Caputo formed Wild Pitch Yeast, a company to sell the strains, in part, to fund his yeast research. The company supplied yeasts isolated from cobwebs, trees and other spots to brewers for making all-Indiana beers, dubbed “Bicentenni-ales” in honor of the state’s 200th anniversary.

Both Bochman and Dunham are relying on brewers to tell them how their newfound yeast perform in the real world. “The proof is in the brewing,” Bochman says. “You can do as many lab tests as you want, but you’re never going to know how something will act until you throw it into some wort and let it bubble away for a couple of weeks.”

Scientists Plan a March on D.C. to Speak Up for Science and Facts

There are certain things that we accept as facts with no alternatives. The Earth is becoming warmer due to human action. The diversity of life arose by evolution. Politicians who devalue expertise risk making decisions that do not reflect reality and must be held accountable. An American government that ignores science to pursue ideological agendas endangers the world.

These are the words written by the organizers of the upcoming Scientists’ March on Washington. The date for the march is not yet set, but it will likely take place, summoning a sea of smart people with a love for science — like you — and the pursuit of knowledge.

The scientific community has been under attack for a while now by Christians who take issue with Darwinian evolution, preferring the Bible’s account. And while nobody wants climate change to be real, it is, though some would rather ignore the supporting evidence and overwhelming consensus of the scientific community to reinforce their own denial. There’s a growing cult of ignorance in which people pride themselves on their lack of scientific knowledge, and it threatens to plunge us all into a new dark age.

Nowhere is this being felt more acutely than in the U.S., where the new Trump administration — along with many Congressional Republicans — is firm in its denial of climate change and in their desire to control the national conversation on a range of scientific issues. Through anti-science appointments, the barring of publications from federal science agencies, and the freeze of all research funding, it all amounts to an unprecedented attack on fact-based knowledge. It’s the chilling — and terrifying — first step of a process in which truth can become whatever a group of politicians say it is.

Caroline Weinberg, one of the march’s organizers, says, “This is not a partisan issue. People from all parts of the political spectrum should be alarmed by these efforts to deny scientific progress. Scientific research moves us forward and we should not allow asinine policies to thwart it.” She adds that science lovers are as welcome as scientists to participate in the march.

It’s not the first time scientists have tried to act as a conscience of a wayward federal government. For example, scientists were key players in the 310,000-person 2014 People’s Climate March. And Harvard science historian Naomi Oreskes, speaking to KQED, reminds us, “It is the scientists who mobilized against the arms race in the late 1950s and 1960s. So that tells you how scientists feel now. This is an existential threat.”

Coastal crops

When Khaled Moustafa looks at a beach, he doesn’t just see a place for sunning and surfing. The biologist at the National Conservatory of Arts and Crafts in Paris sees the future of farming.

In the April issue of Trends in Biotechnology, Moustafa proposed that desalination could supply irrigation water to colossal floating farms. Self-sufficient floating farms could bring agriculture to arid coastal regions previously inhospitable to crops. The idea, while radical, isn’t too farfetched, given recent technological advancements, Moustafa says.

Floating farms would lay anchor along coastlines and suck up seawater, he proposes. A solar panel–powered water desalination system would provide freshwater to rows of cucumbers, tomatoes or strawberries stacked like a big city high-rise inside a “blue house” (that is, a floating greenhouse).

Water desalination could allow farming to take to the sea. The idea sparked the imagination of a Spanish architecture firm, which mocked up an elaborate floating farm complex (illustration). The triple-decker structure would include solar panels on top, crops at midlevel and fish farming on the lower level.

SMART FLOATING FARMS

Each floating farm would stretch 300 meters long by 100 meters wide, providing about 3 square kilometers of cultivable surface over only three-tenths of a square kilometer of ocean, Moustafa says. The farms could even be mobile, cruising around the ocean to transport crops and escape bad weather.

Such a portable and self-contained farming solution would be most appealing in dry coastal regions that get plenty of sunshine, such as the Arabian Gulf, North Africa and Australia.

“I wouldn’t say it’s a silly idea,” Voutchkov says. “But it’s an idea that can’t get a practical implementation in the short term. In the long term, I do believe it’s a visionary idea.”

Floating farms may come with a large price tag, Moustafa admits. Still, expanding agriculture should “be more of a priority than building costly football stadiums or indoor ski parks in the desert,” he argues.

Whether or not farming will ever take to the seas, new desalination technologies will transform the way society quenches its thirst. More than 300 million people rely on desalination for at least some of their daily water, and that number will only grow as needs rise and new materials and techniques improve the process.

“Desalination can sometimes get a rap for being energy intensive,” Dave says. “But the immediate benefits of having access to water that would not otherwise be there are so large that desalination is a technology that we will be seeing for a long time into the future.”

The scorching temperatures mean 2016 is all but certain to be the hottest year ever recorded, beating the previous hottest year in 2015, which itself beat 2014. This run of three record years is also unprecedented and, without climate change, would be a one in a million chance. Scaife says: “Including this year so far, 16 of the 17 warmest years on record have been since 2000 – it’s a shocking statistic.”

By Jef Akst | April 6, 2016

New Gecko-Inspired Adhesive

Flexible patches of silicone that stick to skin and conduct electricity could serve as the basis for a new, reusable electrode for medical applications.

For years, researchers have recreated the microscopic hair-like pillars on gecko feet that, through atomic forces known as van der Waals’ interactions, allow the animals to scurry up walls and across ceilings. Such gecko-inspired adhesives could have a variety of applications, including medical bandages, but materials scientist Seokwoo Jeon at the Korea Advanced Institute of Science and Technology (KAIST) and colleagues wanted to apply these materials to create a novel wearable electrode.

Traditional tattoos last forever because the ink is made of very large molecules. Macrophages, the cells your immune system uses to get rid of stuff like bacteria, just can’t break down the huge dye molecules.

Ephemeral uses a different approach. Lam, another of Ephemeral’s co-founders and the company’s Senior R&D Researcher, said that each dye molecule in their ink is small but it’s encased in a special capsule.

“The reason it’s encapsulated is so that it stays in the skin, so the macrophages can’t eat it up,” Lam said.

These capsules protect the ink from your immune system, but they also can easily be dissolved by a removal solution that Ephemeral has developed. If you decided you no longer want an Ephemeral tattoo, an artist would simply retrace the design with a tattoo gun loaded with the removal solution.

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